Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Operating activities
Net income	$ 58,792	$ 47,389
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	884	1,030
Net amortization of investments	12,306	12,295
Deferred income taxes	(532)	(752)
Net realized (gains) losses on investments	(959)	2,518
Net realized losses on disposal of assets	1	24
Share-based compensation	1,143	691
Changes in operating assets and liabilities:
Premiums receivable, net	(15,623)	(15,169)
Accrued interest receivable	(263)	(571)
Deferred policy acquisition costs	49	(1,440)
Amounts held by others	1,016	(27,847)
Other assets	(2,929)	(1,712)
Reserves for loss and loss adjustment expenses	18,243	33,108
Unearned premiums	7,790	7,694
Reinsurance balances	(11,892)	(5,773)
Amounts held for others and policyholder deposits	6,557	5,682
Accounts payable and other liabilities	8,285	5,555
Net cash provided by operating activities	82,868	62,722
Investing activities
Purchases of investments held-to-maturity	(102,830)	(145,771)
Purchases of investments available-for-sale	(161,482)	(114,406)
Purchases of short-term investments	(12,132)	(7,000)
Proceeds from maturities of investments held-to-maturity	136,896	115,656
Proceeds from sales and maturities of investments available-for-sale	75,470	70,652
Proceeds from sales and maturities of short-term investments	8,033	33,341
Purchases of property and equipment	(1,091)	(759)
Net cash used in investing activities	(57,136)	(48,287)
Financing activities
Proceeds from stock option exercises	837	1,277
Tax benefit from share-based payments	976	1,795
Dividends to shareholders	(10,414)	(8,564)
Net cash used in financing activities	(8,601)	(5,492)
Change in cash and cash equivalents	17,131	8,943
Cash and cash equivalents at beginning of period	69,481	90,956
Cash and cash equivalents at end of period	$ 86,612	$ 99,899